Revision history [back]

I have a dedicated outdoor air system that I am modelling in EnergyPlus. It has a heat exchanger, OAM, Fan, Heating Coil and Cooling Coil. Its function is to supply a constant volume of air (16.625m3/s) between 6am and 8pm at a constant temperature (12.8°C). It is connected into series fan powered boxes in the zones. I have set up the following controls:

1. OA Controller is set to no economizer, minimum limit type - Fixed minimum, Minimum outdoor air schedule is a fraction schedule set to the criteria above. Minimum and maximum air flow rates are both set at 16.625 m3/s.
2. I am using the setpointManager:MultiZone:CoolingAverage to control my cooling coil, and it is set to minimum setpoint temperature 12.8, maximum setpoint temperature 12.8.
3. The Constant volume fan has a fractional schedule that turns it on at 6am and off at 8pm.

When I check the run neither the OA is controlled nor the temperature coming off the cooling coil. The OA varies between 10 m3/s and 16.625m3/s but is at least turned off completely at night, and the air temperature coming off the cooling coil is anywhere between 12.8°C and 21°C.

My suspicion is that I have a series fan powered box connected to the AHU and I have put autosize in the maximum air flow rate box and 0 in the minimum primary air flow fraction box, I have put the correct OA flow rates in the maximum primary air flow rate box though.

Can anyone think of why my DOAS is not behaving itself, or anything I can try to make it work. (note, when we use singleductuncontrolled, and set up the DOAS in the same way the DOAS behaves itself perfectly).

Thanks as always for the help.

I have a dedicated outdoor air system that I am modelling in EnergyPlus. It has a heat exchanger, OAM, Fan, Heating Coil and Cooling Coil. Its function is to supply a constant volume of air (16.625m3/s) between 6am and 8pm at a constant temperature (12.8°C). It is connected into series fan powered boxes in the zones. I have set up the following controls:

1. OA Controller is set to no economizer, minimum limit type - Fixed minimum, Minimum outdoor air schedule is a fraction schedule set to the criteria above. Minimum and maximum air flow rates are both set at 16.625 m3/s.
2. I am using the setpointManager:MultiZone:CoolingAverage to control my cooling coil, and it is set to minimum setpoint temperature 12.8, maximum setpoint temperature 12.8.
3. The Constant volume fan has a fractional schedule that turns it on at 6am and off at 8pm.

When I check the run neither the OA is controlled nor the temperature coming off the cooling coil. The OA varies between 10 m3/s and 16.625m3/s but is at least turned off completely at night, and the air temperature coming off the cooling coil is anywhere between 12.8°C and 21°C.

My suspicion is that I have a series fan powered box connected to the AHU and I have put autosize in the maximum air flow rate box and 0 in the minimum primary air flow fraction box, I have put the correct OA flow rates in the maximum primary air flow rate box though.

Can anyone think of why my DOAS is not behaving itself, or anything I can try to make it work. (note, when we use singleductuncontrolled, and set up the DOAS in the same way the DOAS behaves itself perfectly).

Thanks as always for the help.

I have a dedicated outdoor air system that I am modelling in EnergyPlus. It has a heat exchanger, OAM, Fan, Heating Coil and Cooling Coil. Its function is to supply a constant volume of air (16.625m3/s) between 6am and 8pm at a constant temperature (12.8°C). It is connected into series fan powered boxes in the zones. I have set up the following controls:

1. OA Controller is set to no economizer, minimum limit type - Fixed minimum, Minimum outdoor air schedule is a fraction schedule set to the criteria above. Minimum and maximum air flow rates are both set at 16.625 m3/s.
2. I am using the setpointManager:MultiZone:CoolingAverage to control my cooling coil, and it is set to minimum setpoint temperature 12.8, maximum setpoint temperature 12.8.
3. The Constant volume fan has a fractional schedule that turns it on at 6am and off at 8pm.

When I check the run neither the OA is controlled nor the temperature coming off the cooling coil. The OA varies between 10 m3/s and 16.625m3/s but is at least turned off completely at night, and the air temperature coming off the cooling coil is anywhere between 12.8°C and 21°C.

My suspicion is that I have a series fan powered box connected to the AHU and I have put autosize in the maximum air flow rate box and 0 in the minimum primary air flow fraction box, I have put the correct OA flow rates in the maximum primary air flow rate box though.

Can anyone think of why my DOAS is not behaving itself, or anything I can try to make it work. (note, when we use singleductuncontrolled, and set up the DOAS in the same way the DOAS behaves itself perfectly).

Thanks as always for the help.